High-performance elastic ferroelectrics via low-temperature carbene crosslinking and high-temperature annealing.

Abstract

With the increasing demand for wearable electronics, elastic ferroelectrics with high polarization intensity and Curie temperature have become essential. However, balancing high ferroelectric performance with elasticity in polymeric ferroelectrics remains a challenge, as higher crosslinking density to improve elasticity often compromises Curie temperature and remnant polarization. To address this trade-off, we introduce unsaturated bonds into commercial P(VDF-TrFE), forming P(VDF-TrFE-DB) with enhanced crosslinking reactivity while retaining its inherent ferroelectric properties. A novel two-step LT-HT processing strategy is developed to achieve this balance. The low-temperature (LT) step leverages carbene-mediated crosslinking with diazirine-based crosslinkers below the polymer's Curie temperature, preventing premature crystallization and forming amorphous regions essential for mechanical flexibility. The high-temperature (HT) annealing step promotes the formation and alignment of well-ordered ferroelectric crystalline structures, optimizing remnant polarization and Curie temperature while preserving the crosslinked amorphous regions critical for elasticity. This approach enables high elasticity with minimal crosslinker content while maintaining excellent ferroelectric performance. The resulting elastic P(VDF-TrFE-DB) polymer exhibits a significantly elevated Curie temperature (∼140 °C) and high remnant polarization (7.63 μC cm^-2), comparable to commercial P(VDF-TrFE). This method offers a versatile pathway for advanced flexible electronics, soft actuators, and wearable devices requiring robust mechanical and ferroelectric properties.